Production of fermentation products, such as ethanol, from starch-containing material is well-known in the art. Industrially two different kinds of processes are used today. The most commonly used process, often referred to as a “conventional process”, including liquefying gelatinized starch at high temperature using typically a bacterial alpha-amylase, followed by simultaneous saccharification and fermentation carried out in the presence of a glucoamylase and a fermentation organism. Another well known process, often referred to as a “raw starch hydrolysis”-process (RSH process) includes simultaneously saccharifying and fermenting granular starch below the initial gelatinization temperature typically in the presence of an acid fungal alpha-amylase and a glucoamylase.
Despite significant improvement of fermentation product production processes over the past decade a significant amount of residual starch material is not converted into the desired fermentation product, such as ethanol. At least some of the unconverted residual starch material, e.g., sugars and dextrins, is in the form of non-fermentable Maillard products.
Therefore, there is still a desire and need for providing processes for producing fermentation products, such as ethanol, from starch-containing material that can provide a higher fermentation product yield compared to a conventional process.